System of electric-motor control.



H. D. JAMES.

SYSTEM OF ELECTRIC MOTOR CONTROL.

APPLICATION FILED Ammo, 1908.

1,049,367, Patented Jan. 7, 1913.

- 3 SKEETSSHEET 1.

WTNESSES:

30 I INVENTOR v ATTORNEY H. D. JAMES.

SYSTEM OF ELEGTRIG MOTOR GQN'IROL. APPLICATION FILED APR. 10, 1908.

1,049,367, Patented Jan. 7, 1913.

3 SHEETS-SHEET 2.

' INVENTOR 7 AfiORNEY 7H. D. JAMES. SYSTEM OF ELECTRIC MOTOR CONTROL.

APPLICATION FILED APR.10, 1908. v 1,049,367 Patented Jan. 7, 19,13.

3 SHEETSSHEET 3.

Big. .5.

WITNESSES: mv amoa A.TTORNEY UNITED STATES PATENT OFFICE.

HENRY D. TAKES, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN-MENTS, T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, OF EASTPITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

SYSTEM OF ELECTRIC-MOTOR CONTROL.

Specification of Letters Patent.

Patented J an. 7, 1913.

Application filed April 10, 190B. Serial No. 426,342.

length of time without injury to its wind in s.

Tfly improved system is specially adapted for the control of electricelevators and it embodies an electrically-operated accelerating switch,a manually-controlled reversing switch and the usual series and shuntfield magnet windings for the elevator driving motor. v

Figure l is a partially sectional elevation of the electrically-operatedswitching device which forms a part of my present invention, Fig. 2 isan elevation at right angles to that of Fig. 1, and Fig. 3 is adiagrammatic view of a control system embodying the switching device ofthe other figures and its circuit connections.

Referring to Figs. 1 and 2 of the drawing's, the switching device hereillustrated comprises a stationary frame or castin 1 having ears 2 bywhich it may be secure to an insulating slab or plate, a stationary coremember 3,a movable core member 4, a retarding dash-pot 5, a plurality ofmain circuit, stationary contact members divided into grou s 6 and 7, a.group of auxiliary contact mem is 8 and movable contact members 9, 10,and 11. The three movable contact members are respectively adapted tomake sliding contact with the three groups of stationary contact membersas the movable core member 4 is moved toward the stationary core member3 bythe field of the actuating magnetwinding 12. The frame or casting 1is divided into two parts one of which is the body portion and isprovided with the ears2, as above Indicated, and the other of whichforms a cover 13 that is detachably secured to the body member by meansof bolts 14. The stationa core member 3 is fitted into a hole15 e'upper'end of the frame or casting 1, which is substantially cylindrical inform, and is secured thereto by means of radial pins 16. The movablecore member 4 is supported from the stationary core member by means of arod 17 which extends freely through a hole 18, concentric with the outersurface of the stationary cylindrical core member, and is provided withan enlargement 19 at its upper end. The upper end of the hole 18 iscountenbored to receive a compression spring 20 that is interposedbetween the bottom of the coun tor-bored recess 21' and the enlargement19, for the purpose of taking up the shock which would otherwise comeupon the stationary core member when the magnet is deenergized and themovable core member permitted to drop. The enlargement 19 is providedwith a projection 22 to which the plunger 23 of the dash-pot 5 issecured, by 'a lost-motion connection, the arrangement of parts beingsuch that the upward movement of the movable core member is retarded bythe dash-pot. The movable core member is guided in its travel by meansof abrass sleeve or tube 24; which is secured to the lower end of thestationary coremember by screws 25 and extends downwardly therefrom andin alinement therewith. The upper end of the movable member isfrusto-conical and the lower end of the stationary member is providedwith a recess 26 the walls of which are also frusto-conical to receivethe end of the movable member. The coil 12, which is subcontact members8 are secured, being attached to the projection 28 by means of a bolt31. Bars 32 and 33, which carry the stationary contact members 6 and7,.are secured to the projections 27 and 29 by means of bolts 34 and 35.The lower end of the movable core member 4 is provided with a cross-arm36 to which brush-holders 37 and 38 are secured and which is preventedfrom rotating by means of a longitudinal slot or keyway 39 cut in thecore member and engaged by a projection 40 at the inner f. three partsor fingers members 6 and 7 by means of a spring 42 which is mounted on alongitudinally adjustable spring-support 43 having pin projections 44that extend into the brush holders and force the contact blocks apart.The

auxiliary. movable contact. member 11 is attached to the core member 4and comprises which are designated in Fig. 3 by reference characters 45,46, .and

.47, and are held in engagement with the group 8 of stationarycontactmembers.

Reference -may now behad to Fig. 3, in connection with which theoperation of the switching device and the circuit connections for thesame, maybe described and traced. An electric motor 48, having anarmature 49,a series field magnet winding 50 and a shunt field magnetwinding 51, may be manually controlled by a reversing switch 52 which isadapted to occupy an OK position, as shown in the diagram, and twooperating positions so and y. ,The motor acceleration is automaticallygoverned by the electrically-operated switching device shown in Figs. 1and 2 of the drawings. Assuming that the magnet winding 12 of theaccelerat- 1 member 82 whereupon circuit is established .from contactmember 58 through contact members 59, 82, 81, conductor 83, magnet 60ing switch is-deenergized and thatthe re versing switch occupies itsofl' position; if the latter is moved to its position 00, the motorcircuit connections will be established, as follows: from a positiveline conductor 53 through conductor 54, fuse 55, switch blade 56,conductor 57, contact members 58 and 59 of the reversing switch 52,conductor 60, contact members 61 and 62, conductor 63, armature 49 ofthe motor 48, conductor 64, contact members 65, 66, '67, and 68,conductor 69, series field magnet winding 50,

conductor 70, armature resistance section 71,

the intermediate points ofwhich are connected to the'group 6 ofstationary contact members, bridging contact member 72, resistancesection 73, conductor 74, contact terminals 75 of a switch 85 (which isclosed, as hereinafter pointed out), conductor 76 and switch blade 77,fuse 78 and conductor 79 to negative line conductor 80. Before thecircuit just traced is entirely complete, a contact member 81 of thereversing switch must move into engagement with the contact winding 84of a line switch 85, conductor 86, contact member 87 (which is inengagement with the contact member 47, when the electro-magnet winding12 is deenergized, and the'accelerating resistance is included in themotor circuit), contact members 46 and 88 and conductor 89 to negativeconductor 76. The line switch 85 is thus closed in response to theenergizing of the electro-magnet winding 84 and, at the same time, thecircuit is completed from the contact member 81 through a conductor 90,magnetwinding l2, conductor 91, contact finger 45 (auxiliary resistance92 being now excluded from the circuit), contact member 46 and conductor89 to the negative conductor 76. When this circuit is completed, theelectro-magnet 12 is energized and the movable core'member 4 isattracted ,to-the stationary core member 3 the upward movement oftheformer being retarded by the dash-pot 5. As the movable core memberis raised, the resistance sections 71 and 73 are graduallyshort-circuited' and the auxiliary resistance 92 is gradually introducedinto the circuit of the magnet winding 12-. 'It will be observed thatthe motor is thus gradually accelerated by the reduction of its externalresistance and the current traversing the magnet winding 12 is graduallydecreased as the air-gap existing between the stationary and movablecore members is reduced. \Vhen the magnet has been raised to its fullestextent the resistance sections 71 and 73 are not only short-circuitedbut the series field is also short-circuited in order to still furtherincrease the speed of the motor. F ro'm the conductor 69 the maincircuit is then completed directly through contact member 72, conductor74 and line switch 85 to the line conduct-or 80. When it is desired tostop the motor, the reversing switch is thrown to its oil position, and,in passing from the one position to the other the control circuit lastestablished through the magnet windings 12 and 84 is first broken sothat the motor circuit is always interrupted at the line switch 85 whichmay be specially adapted for accomplishin known iorm ofarc-extinguishing device; If, for any reason, the-movable core member 4should fail to separate itself from the stationary core member when thewinding 12 is denergized, it. will be impossible for the motor to beconnected in circuit until its arthis function by the use of any wellits her 87 when all the resistance is included in i the motor circuit. v

In order to operate the motor'in a reverse direction of rotation,.thereversing switch maybe moved from its ofi position into position :9,when the motor circuit con-nections are so arranged thatcurrent issupplied to the armature 49 in an opposite dimotion. The diagrammaticillustration of the reversing switch is a development of the preferreddevice since it is preferablyv constructed in the form of a drum, the OEposition being located between the positions :v-and' 3 and the movementof the fingers relative to the'drum being indicated by arrows 93. and94. i It is to be understood that structural 5 modifications may beefl'ected in the motoraccelerating switch, and that modifications in thecircuit-connections of the system may be made within the spirit andscopeof my invention,- and I desire that only such limitations shall beimposed as are indicated in the appended claims.

. I claim as my invention:

1.111 a control system,*the combination with a'coinpo'undwound electricmotor and a resistance normally in the armature and series fieldcircuit, of a controller comprising-a stationary and a movable coremember, a magnet winding, and means operatively connected to the movablecore member for accelerating the motor by simultaneously reducing thesaid resistance and the ampere turns of the magnet winding and finallyshort circuiting the series field winding.

2. In a control system, the combination with an electric motor, anelectrically-operated accelerating switch, and a manuallyoperated switchfor governin the action of the accelerat-in switch and or controlling,directly, the irection of rotation of the 80 motor, of means .forclosing the motor circuit and means dependent upon the position of theaccelerating switch for preventing the closure of the motor circuit. V

3. In a control system, the combination with an electric motor, anaccelerating switch therefor comprising stationary and movable coremembers, an operating magnet winding, and means for introducingresistance into the magnet winding circuit as the switch is actuated, anelectrically-operated 40 line switch and a manually-operated reversingswitch which governs the electricallyoperated accelerating and lineswitches and controls the direction of rotation of the motor.

operatively connected to the movable core a member for weakening themagnetic attraction of the stationary core member as the movable coremember approaches thereto.

In testimony whereof, I have hereunto subscribed my name this 30th dayof March, 1908.

HENRY D. JAMES.

Witnesses:

R. J. DEARBORN, BInNEY Hmns.

fio piu 0! this pltent my be obtained for five cents each, by addressingthe Commissioner of l'atents,

. Washington, D. G.

